By Clint Thompson
The Asian citrus psyllid (ACP) is not yet well established in Georgia. University of Georgia (UGA) assistant professor and small fruits pathologist Jonathan Oliver wants to keep that way.
The psyllid vectors citrus greening disease (HLB), which has decimated Florida’s citrus production. Oliver encourages producers to scout their orchards regularly to avoid a similar fate happening in Georgia.
“It’s been found fairly consistently along the coast of Georgia. A lot of our commercial plantings are more inland. We have now found the psyllid a couple of times further inland. There’s probably psyllid out there that we’re not finding,” Oliver said. “We haven’t found it consistently in these other areas, so hopefully, that means these populations are not really well established and it’s not the threat that it is in Florida at this point.
“As far as whether it will become established here, cold spells do reduce the psyllid population pretty dramatically. But we don’t always have a lot of (winter) cold in the southern part of the state or enough to really knock the population back enough. I don’t think relying on our weather conditions to control the psyllid ultimately is going to be enough. Growers really need to be monitoring their fields for the psyllid. If they see it, they need to be putting out effective insecticides to keep those populations down or absent from their planting.”
Georgia has largely avoided citrus greening disease despite its spike in production to 2,700 citrus acres. Oliver said 14 trees have been found to have the disease, 12 of which are homeowner trees. However, two commercial trees were diagnosed with the disease in the past year.
According to UF/IFAS, young citrus trees are most susceptible to HLB and attractive to ACP due to frequent flushing. That is why management of the psyllid is so crucial to the long-term sustainability of Georgia citrus. Imidacloprid and other systemic insecticides can be effective in controlling the pests. However, they are not 100% effective.
“Florida and Brazil have both shown, no matter how much insecticide you put out, you can’t keep the population to zero,” Oliver said. “They do kill the psyllid if they’re applied at the right time in the right place, but it doesn’t mean they completely eliminate the populations. They’re not enough by themselves.”